Jansen graduated from
Stellenbosch University with a BA (Hons) in French and initially worked as an advertising copywriter at De Villiers and Schonfeldt where she was involved in the creation of advertisements for
Rembrandt Group,
Wonderbra,
Caltex, the Dried Fruit Board and other companies. Part of her responsibilities was the translation of the English advertisements into Afrikaans. She obtained a
BA LLB (
cum laude) followed by an
LLM (
cum laude) in property law from
UNISA. The Pretoria Bar Association awarded her the Voet medal (named in honour of
Johannes Voet) for the best final-year law student, as well as the Grotius Medal for most outstanding law student. In 1994, Jansen was appointed an advocate of the Society of Advocates of SA and was appointed a
Senior Counsel. At the time she was one of only two women practicing as advocates; by 2006 there were 80 female advocates but only 3 of them were senior counsel. Clients that she has acted on behalf of include
Cipla Medpro,
Bayer,
McDonald's,
The Body Shop,
Pritt,
Parmalat,
Vodacom,
Kellogg's,
Monsanto,
Cadbury's,
Bakers Limited, the Whisky Association,
Telkom,
Ericsson,
Sasol,
Harley Davidson, Verimark, Mars, the Rembrand companies,
BMW, and
Adcock Ingram. She has appeared in over 150 court cases. Jansen has chaired several Commissions of Enquiry, including the investigation into the misdemeanours of Vice Chancellor A.T. Mokadi of the
Vaal University of Technology, which uncovered fraud and corruption. This led to Mokadi's dismissal, although he was later re-instated (three times) after the charges of fraud and corruption were dropped. She also acted on behalf of the
State Theatre, Pretoria, in the matter of Gaynor Young, who survived a fall of down an open stage shaft at the theatre in 1989. She was appointed a judge of the
Gauteng High Court on 1 December 2013. Jansen has served as a member of the executive committee of the General Council of the Bar; served one term as the vice-chair of the general council and as chair of the Pretoria Society of Advocates in 2003 and 2004. == Controversies ==